Difference between revisions of "Dermatologic neoplasms"

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==Squamous cell carcinoma==
==Squamous cell carcinoma==
{{Main|Squamous carcinoma}}
===General===
Precursor:<ref>TN07 D6.</ref>  
Precursor:<ref>TN07 D6.</ref>  
*Actinic keratosis (solar keratosis).
*Actinic keratosis (solar keratosis).
**Clinical: yellow-brown scaly, patches, sandpaper sensation.
**Clinical: yellow-brown scaly, patches, sandpaper sensation.
Notes:
*Keratocathoma - see ''[[non-malignant skin disease]]''.
*Keratocathoma - see ''[[non-malignant skin disease]]''.
**Some don't believe this entity exists.
**Some don't believe this entity exists.
***These people sign this entity as ''low grade squamous cell carcinoma, keratoacanthoma type''.<ref>RS. 17 May 2010.</ref>
***These people sign this entity as ''low grade squamous cell carcinoma, keratoacanthoma type''.<ref>RS. 17 May 2010.</ref>
===Microscopic===
*See ''[[squamous cell carcinoma]]''.


==Basal cell carcinoma==
==Basal cell carcinoma==

Revision as of 02:52, 28 February 2011

This article deals with dermatologic neoplasms. It includes dermatologic cancer, which can be deadly. Collectively, dermatologic cancers are the most common form of cancer.

Squamous cell carcinoma

Main article: Squamous carcinoma

General

Precursor:[1]

  • Actinic keratosis (solar keratosis).
    • Clinical: yellow-brown scaly, patches, sandpaper sensation.

Notes:

  • Keratocathoma - see non-malignant skin disease.
    • Some don't believe this entity exists.
      • These people sign this entity as low grade squamous cell carcinoma, keratoacanthoma type.[2]

Microscopic

Basal cell carcinoma

General

  • Very common.
  • Sun exposed skin.
  • Very rarely metastasizes - so rare... some don't think this is really a malignancy.

Clinical

  • Telangiectasias.
  • Raised pearly nodule.

As part of a syndrome

Microscopic

Features:[4]

  • Artefactual separation of basal cell layer from underlying stroma.
  • Palisading hyperchromatic cells.

Notes:

DDx:

  • Trichoepithelioma.

Melanoma

General

  • AKA Malignant melanoma.
  • Main DDx: melanocytic lesions - especially if pigmented.
  • Known as the great mimicker in pathology; it may look like many things.

Clinical

  • ABCD = asymmetric, borders (irregular), colour (black), diameter (large).

Microscopic

Features:

  • Classic appearance of melanoma:
    • Loosely cohesive; mix of small nests of cells, single cells.
    • Mixed of spindle and ovoid cell morphology.
    • +/-Occasional large binucleated cells.
    • Cytoplasm: brown pigment (melanin).
    • Prominent (large) red nucleoli (like in serous carcinoma of the ovary).
    • Marked nuclear pleomorphism - variation in cell size, shape & staining (like in serous carcinoma of the ovary).
    • Nuclear pseudoinclusions (like in papillary thyroid carcinoma).

Notes:

  • Can look almost like anything.
    • Like it is said that sarcoidosis is in every internal medicine DDx... melanoma is every pathologic DDx.
  • Melanomas with:
    • An epitheloid cell morphology may mimic adenocarcinoma.
    • A spindle cell morphology may mimic spindle cell carcinoma (squamous cell carcinoma) or a sarcoma.

Electron microscopy

  • Melanosomes.

Image(s):

Stains

  • Fontana-Masson stain, stains melanin.[5]
    • May be useful to differentiate melanin from other brown stuff (e.g. lipofuscin, hemosiderin).

IHC

Standard panel:

  • S-100 +ve.
  • HMB-45 +ve.
  • Melan A (MART-1) +ve.

Others:

  • SOX10 +ve -- useful for diff. from excision scar.[6]
    • SOX-10 = pan-schwannian and melanocytic marker.

Notes:

  • The standard panel above (S-100, HMB-45, MART-1) is also positive in other lesions, e.g. cellular blue nevus.

Dermatofibrosarcoma protuberans

General

  • Abbreviated DFSP.
  • Dermal location.
  • Destroys adnexal structures.

Treatment

  • Wide excision.

Histology

  • Spindle cell morphology.
  • Contains adipose tissue within the tumour -- key feature.

IHC

Panel:[7]

  • CD34 +ve.
    • Usually negative in dermatofibroma.[8][9]
  • Factor XIIIa -ve.
    • Usually positive in dermatofibroma.[8][9]
  • S100 -ve (screen for melanoma).
  • caldesmin -ve (screen for muscle differentiation).
  • beta-catenin ???.
  • MIB-1 (proliferation marker) -- should not be confused with MIB1 a gene that regulates apoptosis.

DDx - histologic

  • Dermatofibroma - has entrapment of collagen bundles at the edge of the lesion.


Cutaneous B-cell lymphoma

  • Abbreviated CBCL.

General

  • CBCL is less common than cutaneous T-cell lymphoma (CTCL).[10]

Microscopic

Features:

  • Dermal lymphoid infiltrate.
  • "Grenz zone" - space between the epidermis and the dermal infiltrate - key feature.

IHC

  • B cell and T cell markers.

Cutaneous T-cell lymphoma

  • Abbreviated CTCL.

General

  • Mycosis fungoides - is a subtype (???).
  • CTCL is more common than cutaneous B-cell lymphoma (CBCL).[11][12]

Microscopic

  • Atypical lymphocytes:
    • Have folded "cerebriform" nuclei; Sezary-Lutzner cells.[13]
  • Grouping:
    • Nests in the epidermis - known as "Pautrier microabscesses".
    • Single lymphocytes in epidermis; "lymphocyte exocytosis".[14]
    • Short linear arrays of lymphocytes along the basal layer of the epidermis; "epidermotropism".[13]

Images:

Merkel cell carcinoma

General

Features:[15]

  • Rare.
  • Aggressive course/poor prognosis.
  • Neuroendocrine-like.[16]

Etiology:

  • Polyomavirus (?).[15]
  • Immunocompromised/immunosuppressed (e.g. organ transplant recipients).

Microscopic

Features:[17]

  • Nests or sheets or trabeculae.
  • Scant cytoplasm.
  • Nuclear moulding.
  • Multiple small nucleoli.
  • Usually mitotically active.

Image:

IHC

  • CK7 -ve, CK20 +ve

Eccrine carcinoma

General

  • Arises from the proximal sweat duct.

Microscopic

Features:

  • Pleomorphic nuclei with nucleoli.
  • Duct-like structures - key feature.
  • Extends from dermis into epidermis (follows path of a benign sweat duct).

Image: Eccrine carcinoma - intermed. mag. (WC).

Eccrine poroma

General

  • Benign tumour arising from the distal sweat duct.
  • Erythematous - gross.

Microscopic

Features:[18]

  • Broad sheets of basaloid cells containing ductal structures - key feature.
  • Biphasic stroma:
    1. Edematous stroma.
    2. Sclerotic stroma.
  • Moderate nuclear pleomorphism.
  • +/-Occasional mitoses.

Notes:

  • Area above gland appears crusted.

Kaposi sarcoma

See Kaposi sarcoma.

See also

References

  1. ↑ TN07 D6.
  2. ↑ RS. 17 May 2010.
  3. ↑ URL: http://emedicine.medscape.com/article/1101146-diagnosis. Accessed on: 6 May 2010.
  4. ↑ NEED REF.
  5. ↑ URL: http://education.vetmed.vt.edu/curriculum/VM8054/labs/Lab2/Examples/exfontana.htm. Accessed on: 5 May 2010.
  6. ↑ Ramos-Herberth FI, Karamchandani J, Kim J, Dadras SS (September 2010). "SOX10 immunostaining distinguishes desmoplastic melanoma from excision scar". J. Cutan. Pathol. 37 (9): 944–52. doi:10.1111/j.1600-0560.2010.01568.x. PMID 20653825.
  7. ↑ AP. May 2009.
  8. ↑ 8.0 8.1 PMID 7694515.
  9. ↑ 9.0 9.1 PMID 9129699.
  10. ↑ URL: http://emedicine.medscape.com/article/1099540-overview. Accessed on: 24 August 2010.
  11. ↑ URL: http://emedicine.medscape.com/article/1099540-overview. Accessed on: 24 August 2010.
  12. ↑ URL: http://emedicine.medscape.com/article/1098342-overview. Accessed on: 24 August 2010.
  13. ↑ 13.0 13.1 Klatt, Edward C. (2006). Robbins and Cotran Atlas of Pathology (1st ed.). Saunders. pp. 385. ISBN 978-1416002741.
  14. ↑ URL: http://www.mdconsult.com/das/book/body/199872830-2/0/1709/I4-u1.0-B978-0-443-06694-8..50117-2--f2.fig. Accessed on: 6 May 2010.
  15. ↑ 15.0 15.1 Calder, KB.; Smoller, BR. (May 2010). "New insights into merkel cell carcinoma.". Adv Anat Pathol 17 (3): 155-61. doi:10.1097/PAP.0b013e3181d97836. PMID 20418670.
  16. ↑ Pulitzer, MP.; Amin, BD.; Busam, KJ. (May 2009). "Merkel cell carcinoma: review.". Adv Anat Pathol 16 (3): 135-44. doi:10.1097/PAP.0b013e3181a12f5a. PMID 19395876.
  17. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 491. ISBN 978-0781765275.
  18. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675(06)70190-5. Accessed on: 2 July 2010.
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